Older lava flows cap mesas on the eastern edge of the field and overlying the monoclinal eastward-dipping western margin of the Rio Grande rift. Cerro Verde, one of the younger centers of volcanism, is a classic basaltic shield volcano that fed lava flows 42 km long. The lava flows are preserved along the margins of the modern Rio San Jose, an eastward draining tributary of the Rio Puerco and Rio Grande.

View east of the Lucero Mesa monocline marking the western margin of the Rio Grande rift. The lava flows of Lucero Mesa were emplaced on an unconformity crossing the tilted layers of the western rift margin. Subsequent landscape erosion has left the lava flow perched or capping elevated mesas where there was once a valley throuygh which the lava flows moved. Photo L. Crumpler.

Geologic map of the Lucero region from the State Geologic Map, New Mexico Bureau of Geology.

Cerro Verde, a classic small shield volcano. Lava flows from this volcanic center moved down the valley of the Rio San Jose several kilometers to the east. Photo L. Crumpler

Cerro Verde shield volcano as viewed from the west near the base of Cerro Colorado ("Volcano Hill"). Photo L. Crumpler